The Effect of C-Rate Variation on Operating Temperature of NMC 5S5P Battery Pack

Abstract

The performance of a Lithium-ion (Li-ion) battery is highly dependent on its operating temperature. Therefore, the Li-ion battery cooling system needs to be investigated when designing a battery pack. The cooling system must be able to maintain the operating temperature of the battery without exceeding its maximum temperature, so that the performance and safety of the battery pack can be guaranteed. This study aims to determine the effect of C-Rate variations on the operating temperature of the NMC battery through a numerical investigation. Lithium-Ion 18650 batteries arranged in a battery module with a 5×5 configuration is evaluated using a forced-liquid cooling system, with water as the coolant. Numerical simulations were run using the ECM heat generation model at different discharge rates of 1C, 2C, 3C, 4C, and 5C for 720 s. The results obtained indicate that the increase in battery pack temperature is directly proportional to the increase in C-Rate. The operating temperature for the five discharge rates is still in the range of safe operating conditions for the battery pack with the maximum temperature difference is below 5°C.